1. Field of the invention
The present invention relates to a power window and more particularly to a power window for use in a vehicular window or the like which power window can prevent sticking of a foreign matter in the vehicular window.
2. Description of Related Art
The number of vehicles equipped with a power window is increasing, which utilizes the driving force of a motor whereby a light touch to an operating switch permits easy opening or closing of the window glass of a door the like. However, when the window glass of a rear seat door is to be opened or closed with an operating switch provided near the driver's seat, the driver sometimes does not become aware of a foreign matter being caught in the window glass due to the presence of a dead angle.
In view of the above point there has been tried to provide a power window with a sticking sensor to prevent sticking of a foreign matter in the window glass of a vehicular door. For example, in JP-A-7-4137, there is disclosed a device which detects the sticking of a foreign matter on the basis of both a detected signal from a window frame sensor, e.g. tape switch, disposed along the peripheral edge of a window frame and a lock signal based on overload of a drive motor.
According to the sticking detecting device disclosed in the above publication, both window frame sensor and locking of the drive motor are used to prevent a malfunction caused by mischief or the like and thereby improve the reliability of detection. However, with the recent spread of the power window, it is desired to further improve the reliability.
Further, the detection sensitivity of a window frame sensor is relatively high [about 5 N (newton) or more], while the detection sensitivity for a drive motor overload is relatively low (about 40 N or more), so by merely taking an AND condition of the detection using a window frame sensor and that using a drive motor there arises the problem that a fairly large sticking force is already exerted even if the window glass is started to operate in the reverse direction, or opening direction, at the time of detection.